Insulating ring and method of making the same



June 22 1926. 1,589,464

- L. T. FREDERICK INSULATING RING AND METHOD OF MAKING THE SAME FiledJune 7, 1924 c [02:03 reaerzdf Patented June 22, 1926.

UNITED STATES 1,589,464 PATENT OFFICE.

LOUIS '1. FREDERICK, OI VALPABAIBO, INDIANA, ASSIGNOR T0 CHICAGO IIOA0O!- PANY, OI VALPARAIBO, INDIANA, A CORPORATION 01 ILLINOIS.

' mlULA'1ING RING AND METHOD 0] MAKING THE an Application filed June 7,

M invention relates to insulating bodies of t c class used,-for example,in electric motors and generators to insulate various parts of theapparatus from each other. My invention relates particularly toinsulating bodies having annular flanges of various shapes and theobject of the invention is to produce a body of this character whichshall be eflicient as an insulator and at the same time possessed of a.high degree of strength and uniformity of structure. My invention isespecially useful in connection with the formation of insulating bodiesor rings formed of mica plate. Mica plate is a known article andconsists of mica flakes held together by shellac or other suitablebinder. It is plastic when hot and may be configurated by subjection toheat and pressure. It is known to form rings from mica plate, butaccording to methods heretofore employed the flanges have not been ofuniform strength or consistency throughout their ri hery. The flangingrocess has cause a istortion in the material and frequentl the mica hasbeen crushed toa perceptib e degree, thus 'weakening both its structuraland its di-electric properties.

My purpose is to obtain a simple and re-.

liable method by which these imperfections may be avoided and a ring ofuniform strength produced free from internal stresses and strains and ofuniform consistency.

I accom lish my object in the manner illustrated in the accompanyingdrawings in which Figure 1 shows three discs of mica plate or similarsheet material from-which a ring may be produced. These are shown withslots in their periphery and are separated for the purpose of showingtheir outline.

Figure 2 1s a view similar to Figure 1 but showing the sheets superposedin contact with each other.

Figure 3 is a perspective pleted ring.

Figures 4, 5 and 6 are diametral sectional views of difierentconfiguration.

Like numerals denote like parts throughout the several views.

In practicing my process I first produce the sheet material,- referablymica plate composed of flakes o mica held together by she ac or othersuitable binder. This sheet material is plastic in the sense that it canview of a com- 1924. Serial No. 718,481.

be configurated when hot. From this sheet material I produce a number ofblanks, typical ones of which are shown in Figure 1 and indicated by thereference numeral 1. In the case illustrated they are circular inoutline and have radial slots 2 cut in their peripheries at spacedintervals. Usually .these slots are in the form of sectors arrangedradially although their sides may or may not be exactlg radial, thisdepending upon the shape of t e flange ultimately. de'.

sired. Ordinarily the an le will be such that when the flange is nallyformed the tongues or. dovetails will "come edge to Y edge orapproximately so. 'l-.he-sheets thus prepared may be referred tojasthe'blanks.

'After they areformed," the blanks to a predetermined number are laidone upon another in stag Figure 2, that 1s, they are superposed in sucha manner that the slots are out of register and the slots of one sheetwill come opposite to the blank portions or tongues 3 of the adjacentsheet. I The pile of blanks thus arranged is then subjected to theaction of a drawing die. Mica plate is plastic when hot and the die maybe heated if desired, but I have found that by preparing and arrangingthe blanks in the manner described, excellent results may be obtained byheating the blanks beforehand and inserting them while hot into a colddie. By this method the material' is already plastic before reaching thedie and the die, being cool, will rapidly configurate the material andpromptly cool it. This greatly increases the output over the amount thatcould be obtained by employing a heated .die. In either case thepressure of the die not onl configurates the material but also binds t elaminations into a sin le unitary structure. Apparently the bin er isforced from the body of the mica sheets partly onto the surface of thesheets and being hot thus cements the sheets together. In the finishedarticle the laminations are not apparent and the article has theappearance of a solid close knit structure.

A suitable die may be made in different ways and its configuration willdepend upon the configuration desired in the ultimate product. InFigures 4, 5 and 6 I have shown finished products of diiferent form. Theform (1 shown in Figure 4 is frequently denominated in the trade a Vring that red relation as shown in.

shown in Figure a Z ring and that shown in Figure 6 an L ring. Whileelec tric motors and generators usually require rings in which thecentral portion. is cut awa it will be evident that the same met 0d maybe applied to the production of cup shaped or plain dished bodies, the

central portion first, as the ortion removed can then be used for prouoing rings of smaller sizes.

It will be evident by referring to Figure 3 that the finished ring whenmade' in accordance with the preferred proportions will have a flange 5in which the tongues 3 are closed up in the sense of having their edgessubstant ally in contact with each other and the flanges will becomposed of a plurality of layers of tongues which overlap each other.Thus the ring may be said to have a composite butt and lapped flange.

Rings produced in this manner possess remarkab e strength and uniformitystructurally and uniform'insulating properties It will be evident thatthe mica in the flanges is configurated without being crushed ordistorted. Mica has a crystalline structure and if. subjected to unduepressure or stress of any kind will tend to crush. Such crushing occurswhere the flanges are not notched and are configurated by a meredrawing,

and the ring is formed of a single sheet instead of a pluralityof thinsuperposed sheets. In bodies produced by my process and havinglaminations of mica sheets with butt and lapped flanges there is nodistortion nor. 'crushing and the finished articlel is stripng and ofuniform properties throughon While my invention is especially applicableto mica plate it is not necessarily confined thereto for other plasticsheet material may be employed. For example, the sheet material mayconsist of canvas or other woven fabric impregnated with a binder otherthan shellac, for example, condensation product sometimes calledsynthetic resin and produced by reacting formaldehyde and phenol in thepresence 01% a reaent. It is known to produce hard bodies y subjectingto the action of heat and pressure layers of woven fabric saturated insuch condensation product and I may apply the prlnclple of my inventioneither to mica sheetsor to woven fabric saturated in such condensationproduct. In using condensatron product as a binder, however, a subse--material to permit configuration of the sheet without distortion.

2. An insulating body having an annular flange and composed of aplurality of laminations of plastic sheet material, each sheet havingsector shaped slots to permit the flange to be formed Without distortionand the slots being staggered to produce a lap- 3. An insulating ringhaving a central opening and an integral flange, the ring being composedof circular, concentric laminations of mica plate and the flangedportion being of butt and lapped construction.

4. The method of making insulating.

bodies consisting in taking a plurality of layers of circularmica sheetspiling them concentrically and subjecting them while hot to the actionof a drawing die.

5. The method of making flanged insulating bodies consisting ofpreparing a plurality of sheets of plastic insulating material havingradial slots in the periphery, staggering the sheets so that the slotsshall be out of register, and subjecting the pile of sheets while hot tothe action of a drawing dieto' produce a flange from the slotted portionof the sheets.

6. The method of producing flanged in- I sulating bodies consisting inpreparing a plurality of blanks of plastic insulating material, cuttingnotches in the periphery of the blanks, arranging the blanks in a pilewith the notches out of register, heating the blanks to render themplastic, and subjecting the pile of blanks while in plastic condition tothe pressing action of a drawing die to thereby produce a lapped flangeand simultaneously unite the blanks to each other. I

7. The method of producing flanged insulating bodies consisting inpreparing a plurality of circular blanks of mica plate, cutting sectorshaped slots at spaced intervals in the periphery of the blanks,arranging the blanks in a pile with the sectors out of register, heatingthe material to render it plastic, and while the material is plasticforming an annular flange in the pile of blanks to an extent which willcause the dovetails between sectors to meet edge to edge.

8. The method of producing insulating rings consisting in preparing aplurality of circular blanks of mica plate, cutting sector sha (1 slotsat s aced intervals in the perip cry of the b ank, arran g the blanks ina pile with the tongues etween sectors overlapping each other, heatingthe material to render it plastic, and while the material is plasticforming an annular flan e in the ile of blanks to an extent which willcauset he tongues to close up, substantially edge to edge, and chillingthe material simultaneously with the forming operation.

9. The method of roducing insulating rings and the like consisting inmaking thin sheets composed of mica flakes and a binder capable ofbecoming plastic when heated, preparing circular blanks from saidsheets,

LOUIS T. FREDERICK.

